Visible Light-induced Organic Dye-catalyzed Synthesis Of Aryl N-heterocyclic Compounds

Aryl N-heterocyclic compounds are widely used in the field of drug synthesis.At present,these compounds are mainly synthesized by light-induced metal complexes.The metal complexes used are mainly complexes of noble metals such as ruthenium and iridium.Because precious metals are expensive and difficult to recycle,this article intends to choose inexpensive organic dyes as catalysts,and to study the reaction process of synthesizing aryl N-heterocyclic compounds by changing the types of organic dyes and operating conditions The correspondingresults are as follows:1.According to the characteristics of the reaction characteristics,material properties and separation methods of the synthesis of aryl N-heterocyclic compounds,a process flow for the synthesis of aryl N-heterocyclic compounds was constructed,which was prepared by solution preparation,diazotization reaction,solid-liquid separation,drying,and aromatics.The aryl N-heterocyclic compound can be synthesized by process steps such as radicalization reaction,extraction,evaporation,and leaching.Four different diazobenzene tetrafluoroborates were selected to react with four different N-heterocyclic aromatic hydrocarbons,and 14 aryl N-heterocyclic compounds were synthesized by visible light-induced Eosin Y catalysis.The infrared spectroscopy method was used.The product was analyzed and determined by liquid phase-mass spectrometry and nuclear magnetic resonance spectroscopy.The research results show that the arylation reaction mostly occurs at the ortho position of N;quinoxaline,p-trifluoromethylpyridine and diazobenzene tetrafluoroborate are not detected under the reaction conditions.2.Using p-cyanopyridine and p-bromodiazonobenzene tetrafluoroborate diazonium salt as raw materials,2-(4-bromophenyl)-p-cyanopyridine was synthesized by visible light-induced organic dye catalysis.The concentration and concentration were determined by the standard curve method.The yield was calculated,and the influence of light source,reaction time,catalyst type,catalyst dosage,and molar ratio of reactants on the yield was studied.The research results show that the light source has a significant effect on the yield.The reaction yield under blue light irradiation reaches 36%,and the reaction yield under white light irradiation is only 3%;the catalytic effect of the four catalysts is from high to low:Eosin Y,Rhodamine B,Eosin B,Rose Bengal;as the reaction time increases,the yield increases to 47%and then gradually decreases;the influence of the amount of catalyst on the yield is similar to the reaction time;with the increase of the reactant ratio,The yield is basically unchanged after gradually increasing to 45%.Under 3 W blue light irradiation,5 mmol p-cyanopyridine and 1 mmol p-bromodiazonobenzene tetrafluoroborate are catalyzed by 0.05 mmol eosin Y and 0.01 mmol trifluoroacetic acid,and arylation reaction can occur to synthesize 2-(4-Bromophenyl)-p-cyanopyridine,when the reaction was carried out for 22 hours,the yield reached 56%.3.Using pyrazine and p-bromodiazonobenzene tetrafluoroborate diazonium salt as raw materials,2-(4-bromophenyl)-pyrazine was synthesized by visible light-induced organic dye catalysis.The concentration and yield were determined by standard curve method.The effects of light source,reaction time,catalyst type,catalyst dosage,and reactant molar ratio on the yield are discussed.The research results show that the light source has a significant effect on the yield.The reaction yield under blue light irradiation reaches 44%,and the reaction yield under yellow light irradiation is only 9%.The catalytic effect of the four catalysts is from high to low:Rhodamine B,Eosin Y,Eosin B,Rose Bengal;With the increase of the reaction time,the yield gradually increases to 60%and then basically unchanged;the influence of the amount of catalyst on the yield is similar to the reaction time;with the proportion of reactants After the increase in the yield,the yield gradually increased to 58%and remained basically unchanged.Under 3 W blue light irradiation,6 mmol pyrazine and 1 mmol p-bromodiazonobenzene tetrafluoroborate are catalyzed by 0.06 mmol Rhodamine B and 0.01 mmol trifluoroacetic acid,and arylation reaction can occur to synthesize 2-(4-Bromophenyl)-pyrazine,when the reaction was carried out for 28 hours,the yield reached 69%.